1. Field of the Invention
The present invention relates to a display system for an elevator which is preferable to be used when displaying an operating state of an elevator car at a predetermined position in, e.g., an ultrahigh-speed elevator, and an information display device used in this system.
2. Description of the Related Art
In an elevator, an operating state of an elevator car is constantly monitored by an elevator control device which is called a “control board”. Data concerning an operating state of this elevator car is transferred to an information display device or the like in the elevator car through a transmission cable.
Here, in a regular elevator, data concerning an operating state of an elevator car is periodically transferred from an elevator control device in accordance with a timing at which the elevator car moves to each floor. Therefore, on the information display device side, an operating state of the elevator car can be displayed in real time based on these data.
Meanwhile, in a superultrahigh-speed elevator whose rated speed (a maximum speed) exceeds, e.g., 1000 m/min, an elevator car moves between respective floors at a very high speed. Therefore, data transfer from an elevator control device to the elevator car is unable to follow a speed of the elevator car, and there occurs a problem that a position of the elevator car is intermittently displayed like “50th floor”→“52th floor”→“54th floor” . . . , for example.
There has been conventionally known, e.g., Jpn. Pat. Appln. KOKAI Publication No. 1994-247654 which eliminates a delay of a display timing due to an increase in speed of such an elevator. In this publication, when an elevator car has passed through an intermediate position between floors, a display switching signal is generated from an elevator control device side, thereby directing an information display device to switch display in accordance with each floor ahead of time.
However, a method of adjusting a timing on the elevator control device side has a limit. Therefore, the elevator car may possibly pass through a floor as a display target before display is switched on the information display device side upon receiving the display switching signal.
As described above, when an elevator car travels at high speed, there is a problem that data transferred from an elevator control device to the elevator car is delayed so that a position or the like of the elevator car is intermittently displayed. In this case, the above-described problem can be eliminated by, e.g., increasing data transfer performance of the elevator control device. However, there is a demerit that a cost involved by an improvement in performance is required and an existing control device cannot be used.